kernel/block/blk-core.c, branch linux-5.1.y

blk-mq: move cancel of requeue_work into blk_mq_release

2019-06-15T09:52:58Z

[ Upstream commit fbc2a15e3433058582e5635aabe48a3011a644a8 ] With holding queue's kobject refcount, it is safe for driver to schedule requeue. However, blk_mq_kick_requeue_list() may be called after blk_sync_queue() is done because of concurrent requeue activities, then requeue work may not be completed when freeing queue, and kernel oops is triggered. So moving the cancel of requeue_work into blk_mq_release() for avoiding race between requeue and freeing queue. Cc: Dongli Zhang Cc: James Smart Cc: Bart Van Assche Cc: linux-scsi@vger.kernel.org, Cc: Martin K . Petersen , Cc: Christoph Hellwig , Cc: James E . J . Bottomley , Reviewed-by: Bart Van Assche Reviewed-by: Johannes Thumshirn Reviewed-by: Hannes Reinecke Reviewed-by: Christoph Hellwig Tested-by: James Smart Signed-off-by: Ming Lei Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

blk-mq: free hw queue's resource in hctx's release handler

2019-05-25T16:16:18Z

commit c7e2d94b3d1634988a95ac4d77a72dc7487ece06 upstream. Once blk_cleanup_queue() returns, tags shouldn't be used any more, because blk_mq_free_tag_set() may be called. Commit 45a9c9d909b2 ("blk-mq: Fix a use-after-free") fixes this issue exactly. However, that commit introduces another issue. Before 45a9c9d909b2, we are allowed to run queue during cleaning up queue if the queue's kobj refcount is held. After that commit, queue can't be run during queue cleaning up, otherwise oops can be triggered easily because some fields of hctx are freed by blk_mq_free_queue() in blk_cleanup_queue(). We have invented ways for addressing this kind of issue before, such as: 8dc765d438f1 ("SCSI: fix queue cleanup race before queue initialization is done") c2856ae2f315 ("blk-mq: quiesce queue before freeing queue") But still can't cover all cases, recently James reports another such kind of issue: https://marc.info/?l=linux-scsi&m=155389088124782&w=2 This issue can be quite hard to address by previous way, given scsi_run_queue() may run requeues for other LUNs. Fixes the above issue by freeing hctx's resources in its release handler, and this way is safe becasue tags isn't needed for freeing such hctx resource. This approach follows typical design pattern wrt. kobject's release handler. Cc: Dongli Zhang Cc: James Smart Cc: Bart Van Assche Cc: linux-scsi@vger.kernel.org, Cc: Martin K . Petersen , Cc: Christoph Hellwig , Cc: James E . J . Bottomley , Reported-by: James Smart Fixes: 45a9c9d909b2 ("blk-mq: Fix a use-after-free") Cc: stable@vger.kernel.org Reviewed-by: Hannes Reinecke Reviewed-by: Christoph Hellwig Tested-by: James Smart Signed-off-by: Ming Lei Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

block: Revert v5.0 blk_mq_request_issue_directly() changes

2019-04-05T15:40:46Z

blk_mq_try_issue_directly() can return BLK_STS*_RESOURCE for requests that have been queued. If that happens when blk_mq_try_issue_directly() is called by the dm-mpath driver then dm-mpath will try to resubmit a request that is already queued and a kernel crash follows. Since it is nontrivial to fix blk_mq_request_issue_directly(), revert the blk_mq_request_issue_directly() changes that went into kernel v5.0. This patch reverts the following commits: * d6a51a97c0b2 ("blk-mq: replace and kill blk_mq_request_issue_directly") # v5.0. * 5b7a6f128aad ("blk-mq: issue directly with bypass 'false' in blk_mq_sched_insert_requests") # v5.0. * 7f556a44e61d ("blk-mq: refactor the code of issue request directly") # v5.0. Cc: Christoph Hellwig Cc: Ming Lei Cc: Jianchao Wang Cc: Hannes Reinecke Cc: Johannes Thumshirn Cc: James Smart Cc: Dongli Zhang Cc: Laurence Oberman Cc: Reported-by: Laurence Oberman Tested-by: Laurence Oberman Fixes: 7f556a44e61d ("blk-mq: refactor the code of issue request directly") # v5.0. Signed-off-by: Bart Van Assche Signed-off-by: Jens Axboe

mm: refactor readahead defines in mm.h

2019-03-12T17:04:01Z

All users of VM_MAX_READAHEAD actually convert it to kbytes and then to pages. Define the macro explicitly as (SZ_128K / PAGE_SIZE). This simplifies the expression in every filesystem. Also rename the macro to VM_READAHEAD_PAGES to properly convey its meaning. Finally remove unused VM_MIN_READAHEAD [akpm@linux-foundation.org: fix fs/io_uring.c, per Stephen] Link: http://lkml.kernel.org/r/20181221144053.24318-1-nborisov@suse.com Signed-off-by: Nikolay Borisov Reviewed-by: Matthew Wilcox Reviewed-by: David Hildenbrand Cc: Jens Axboe Cc: Eric Van Hensbergen Cc: Latchesar Ionkov Cc: Dominique Martinet Cc: David Howells Cc: Chris Mason Cc: Josef Bacik Cc: David Sterba Cc: Miklos Szeredi Cc: Stephen Rothwell Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

block: pass no-op callback to INIT_WORK().

2019-01-30T15:53:20Z

syzbot is hitting flush_work() warning caused by commit 4d43d395fed12463 ("workqueue: Try to catch flush_work() without INIT_WORK().") [1]. Although that commit did not expect INIT_WORK(NULL) case, calling flush_work() without setting a valid callback should be avoided anyway. Fix this problem by setting a no-op callback instead of NULL. [1] https://syzkaller.appspot.com/bug?id=e390366bc48bc82a7c668326e0663be3b91cbd29 Signed-off-by: Tetsuo Handa Reported-and-tested-by: syzbot Cc: Tejun Heo Signed-off-by: Jens Axboe

Revert "block: cover another queue enter recursion via BIO_QUEUE_ENTERED"

2019-01-27T13:35:28Z

We can't touch a bio after ->make_request_fn(), for all we know it could already have been completed by the time this function returns. This reverts commit 698cef173983b086977e633e46476e0f925ca01e. Reported-by: syzbot+4df6ca820108fd248943@syzkaller.appspotmail.com Signed-off-by: Jens Axboe

block: cover another queue enter recursion via BIO_QUEUE_ENTERED

2019-01-22T17:24:08Z

Except for blk_queue_split(), bio_split() is used for splitting bio too, then the remained bio is often resubmit to queue via generic_make_request(). So the same queue enter recursion exits in this case too. Unfortunatley commit cd4a4ae4683dc2 doesn't help this case. This patch covers the above case by setting BIO_QUEUE_ENTERED before calling q->make_request_fn. In theory the per-bio flag is used to simulate one stack variable, it is just fine to clear it after q->make_request_fn is returned. Especially the same bio can't be submitted from another context. Fixes: cd4a4ae4683dc2 ("block: don't use blocking queue entered for recursive bio submits") Cc: Tetsuo Handa Cc: NeilBrown Reviewed-by: Mike Snitzer Signed-off-by: Ming Lei Signed-off-by: Jens Axboe

block: fix kerneldoc comment for blk_attempt_plug_merge()

2019-01-09T22:29:08Z

Commit 5f0ed774ed29 ("block: sum requests in the plug structure") removed the request_count parameter from block_attempt_plug_merge(), but did not remove the associated kerneldoc comment, introducing this warning to the docs build: ./block/blk-core.c:685: warning: Excess function parameter 'request_count' description in 'blk_attempt_plug_merge' Remove the obsolete description and make things a little quieter. Signed-off-by: Jonathan Corbet Signed-off-by: Jens Axboe

block: clarify documentation for blk_{start|finish}_plug

2019-01-09T03:49:46Z

There was some confusion about what these functions did. Make it clear that this is a hint for upper layers to pass to the block layer, and that it does not guarantee that I/O will not be submitted between a start and finish plug. Reported-by: "Darrick J. Wong" Reviewed-by: Darrick J. Wong Reviewed-by: Ming Lei Signed-off-by: Jeff Moyer Signed-off-by: Jens Axboe

block: clear REQ_HIPRI if polling is not supported

2018-12-16T16:01:38Z

This prevents a HIPRI bio from being submitted through a stacking driver that does not support polling and thus won't poll for I/O completion. Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe